Another soldier attached to the 101st has been detained and is being questioned in connection with the incident early Sunday at one of the division's camps in northern Kuwait, Army V Corps spokesman Max Blumenfeld said.

The attack at Camp Pennsylvania, where soldiers from the 101st Airborne Division are stationed, wounded 12 people -- at least five of them seriously -- U.S. military officials said.

Financial Times correspondent Charles Clover -- who is embedded with the unit -- said he was told by Col. Ben Hodges, a commander of the 1st Brigade, that the soldier lobbed three grenades into the three tents housing commanding officers from the tactical operations center. At least two of the grenades exploded, Hodges told Clover.

Two people were wounded by gunfire, Clover said, the others by fragments.

Central Command said two were treated at the scene, and the 11 others were taken by helicopter to Army combat support hospitals in the region. The conditions of the other 10 are unknown.

The Army criminal investigation command is probing the incident.

Video obtained by CNN showed the suspect sitting on the ground with his legs in front of him. His head was partially covered by his camouflage jacket, and he appeared to have bloodstains on his leg and his back or arm.

A base spokesman at Fort Campbell, Kentucky, where the 101st is based, said news of the incident upset families at the base was a blow to morale.

Military criminal investigators said the suspect was recently reprimanded for insubordination and was told he would stay behind when his unit left camp for Iraq, Time reporter Jim Lacey said.

Lacey said he was told by a military commander that the soldier lobbed three grenades into the operations center and yelled, "You're under attack!" A major told Lacey he saw a grenade roll by him before an explosion.

Soldiers carry away one of the wounded.

Lacey, who was in a tent about 20 yards from the blast, helped move two of the wounded to an ambulance. "The carnage inside those tents was pretty severe," he said.

Lacey said a "full company" of soldiers was guarding the camp's perimeter before the blast, but there had been traffic in and out, including "trucks, buses, and contractors. It's not a foolproof system."

About 2,100 soldiers are encamped at the post. Lacey said soldiers were assembled and deployed around the compound after the blast.